Incidence, severity, and onset of oral mucositis in 5-FU based chemotherapy for gastrointestinal cancer.

77 Background: 5-fluorouracil has been used in treatment of gastrointestinal cancers for more than 40 years. Numerous toxicities of 5-FU are known. Little is known about the occurrence, natural course and causes of oral mucositis (OM) of 5-FU in GI tumors. There is little data on the additional toxicity of VEGF and EGFR antibodies together with 5-FU. We followed the occurrence, severity and localization of OM of 5-FU in consecutive patients as part of their cancer treatment. The primary aim of the study was to determine the severity, course and risk factors of OM up to the first six cycles of ctx. OM was evaluated by repeated inspections of the oral cavity and patient questionnaires. Methods: Pts who received 5-FU for the first time or who had not received ctx for at least 12 months. 64 consecutive pts were included in the observational study from March 2018 to March 2019. Out of 64 pts a total of 41 (28 m/13f) had complete documentations (inspections of the oral cavity and questionnaires) and were available for the evaluation. Results: Mean age 65 ys (range 42-83), 60% were treated for CRC, 22% esophageal/gastric cancer, and 18% other GI-cancers. 13 were non-smokers, 25 former smokers; 7 pts had daily alcohol consumption while 7 pts never consumed alcohol. 10/41 pts wore a dental prosthesis. The mean BMI was 26.5 (range 18.8-41.5). Initial very good/ good oral hygiene was given in 3/20 patients. 80% of the pts developed xerostomia after the first cycle, almost every patient needed support for symptoms due to oral problems during ctx. Of 41 pts, an OM could be documented in 38 pts. A total of 93% of the patients developed a mild course of the mucositis with grade 1-2. OM developed between the 2 nd and 3 rd cyle in the majority of pts. At the third cyle, only 8 pts had OM of grade 0, while 23 pts had grade 1 and 9 pts were grade 2. It was of note here that of these 9 pts with grade 2, 6 had grade 0 in the 2nd cycle. During cycle 5 and 6 only seven pts had a CTC score of 0, but no pat developed a CTC 3 or 4 OM. We could not document a connection between the occurrence of oral mucositis and the oral hygiene measures used, as no severe course of OM CTC Grad 3 or 4 could be detected. We could not find any relation to the type of 5-FU therapy (doublet, triplet +/- monoclonal antibodies). Conclusions: The incidence of oral mucositis with CTC score of 1 and 2 was 93%, but serious grade 3 and 4 mucositis rates were not observed. Xerostomia was observed in 80% after the first course of treatment. Symptomatic mucositis occurs early within 4 weeks after starting chemotherapy. Local measures appear suitable for symptom control of OM.